--- before/app/models.py
+++ free/app/models.py
@@ -1,22 +1,22 @@
-from pydantic import BaseModel, validator
+from pydantic import field_validator, ConfigDict, BaseModel
 
 
 class Order(BaseModel):
     customer: str
     quantity: int
 
-    @validator("customer")
+    @field_validator("customer")
+    @classmethod
     def normalize_customer(cls, value):
         value = value.strip()
         if not value:
             raise ValueError("customer required")
         return value
 
-    @validator("quantity")
+    @field_validator("quantity")
+    @classmethod
     def positive_quantity(cls, value):
         if value < 1:
             raise ValueError("quantity must be positive")
         return value
-
-    class Config:
-        extra = "forbid"
+    model_config = ConfigDict(extra="forbid")
--- before/app/settings.py
+++ free/app/settings.py
@@ -1,8 +1,6 @@
-from pydantic import BaseSettings
+from pydantic_settings import BaseSettings, SettingsConfigDict
 
 
 class Settings(BaseSettings):
     service_name: str = "Order API"
-
-    class Config:
-        env_prefix = "ZIPPER_PROOF_"
+    model_config = SettingsConfigDict(env_prefix="ZIPPER_PROOF_")
--- before/manual_review.py
+++ free/manual_review.py
@@ -4,6 +4,8 @@
 class LegacyOrder(BaseModel):
     quantity: int
 
+    # TODO[pydantic]: We couldn't refactor the `validator`, please replace it by `field_validator` manually.
+    # Check https://docs.pydantic.dev/dev-v2/migration/#changes-to-validators for more information.
     @validator("quantity")
     def dependent_validation(cls, value, values):
         return value